Background/Rationale: Black-White disparities in control of hypertension and diabetes contribute to U.S. racial disparities in life expectancy. Within VA, higher rates of uncontrolled hypertension or diabetes have been identified in several racial/ethnic minority groups, compared with white Veterans. The extent to which socio- economic status (SES)-related differences drive these racial-ethnic disparities is unknown. Patient Aligned Care Teams (PACT) hold promise as a care delivery model to reduce disparities, however, implementation is variable, particularly in sites with large proportions of minorities. Though traditional medical models cannot directly change most social determinants of health like SES, facilities can adapt their delivery approaches to better meet the needs and healthcare delivery preferences of their patients, e.g., incorporating evidence-based interventions associated with improved hypertension or diabetes control in vulnerable groups, and in that way influence outcomes indirectly. Appraisal of multi-level factors (healthcare system, site, patient) associated with improved outcomes in vulnerable groups (racial/ethnic minorities and the lowest quintile SES), and elucidation of implementation barriers, may inform VA strategies for tackling low quality and ameliorating high disparities. Specific Aims: Aim #1: Characterize associations between vulnerable group and quality (measured by intermediate clinical outcome quality measures hypertension and diabetes control): (a) Determine variations by race/ethnicity and SES in hypertension and diabetes care quality; (b) Examine SES as a mediator and moderator of the relationship between race/ethnicity and quality; and (c) Identify multi-level predictors of quality and disparities. Aim #2: Identify VA sites representing extremes in vulnerable group quality and disparities ? high quality-low disparity ?positive deviant? sites, high disparity sites (high quality for majority groups, low quality for vulnerable groups), and low performing sites (low quality for both majority and vulnerable groups) ? and describe characteristics of those sites. Aim #3: Compare positive deviant, high disparity, and low performing sites: (a) Assess clinical practice delivery arrangements for hypertension and diabetes care, particularly evidence-based approaches associated with disparities reduction, and contextual factors identified in Aim #1; and (b) Identify barriers to and facilitators of effective implementation of those delivery arrangements. Methods: We propose a mixed-methods observational study using primary and secondary data sources to achieve these aims. For Aims #1 and #2, we will use a national cohort of all Veterans using VA in fiscal year 2017, with their individual socio-demographics, diagnosed conditions, and residential characteristics linked with existing data on VA site and healthcare system characteristics, including site-level PACT implementation and healthcare system-level patient experience from VA quality metrics, and then linked to electronic quality measures. We will determine site-specific performance for vulnerable and majority groups, and disparities between these groups, then identify sites representing extreme examples of quality and disparities based on decision rules applied to graphical displays of this data. For Aim #3, we will conduct key stakeholder interviews at those sites, to explore local practices for achieving hypertension and diabetes control in their patients, including barriers, facilitators, and contextual factors influencing implementation of evidence-based practices. Anticipated Impacts on Veterans Health: This research will fill a knowledge gap about the prevalence of VA disparities related to socio-economic vulnerability, provide evidence on clinical practice delivery arrangements associated with higher quality and lower disparities for vulnerable groups, and provide effective field-tested disparities-reduction approaches to inform evidence-based quality improvement initiatives and implementation research to improve clinical outcomes for vulnerable groups at low-performing or high disparity VA sites.